Wayland Town Crier 8/25/11: Kinetic artist David Lang's work is always moving. An artist with a feverish mind and patient hands, David A. Lang had been wondering what materials he needed to make a moving sculpture that would express his fascination — maybe his obsession — with "uncertainty, unpredictability and serendipity." So he began bugging friends and advertising on eBay for bedpans. In a Natick studio that resembles a cross between Geppetto's workshop and the Unabomber's cabin, Lang transformed five donated bedpans into an airborne mobile titled "Fleet" that'll float beneath a canopy of fluttering paper wings in his soon-to-open exhibit at the Boston Sculptors Gallery.